| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a photosensor and to improve cooling efficiency. SOLUTION: A first Peltier element Pe1 and one or more second Peltier elements Pe2 having the current consumption smaller than that of the first Peltier element Pe1 are connected in series, and a bypass circuit B shunting the excess current I3 to the second Peltier elements Pe2 is connected in parallel with the second Peltier elements Pe2. The first Peltier element Pe1 is driven at the optimum operation point by the drive current I1 from a current controller A, the excess current I3 to the second Peltier elements Pe2 within the drive current I1 is shunted to the bypass circuit B so that the second Peltier elements Pe2 can be driven at the optimum operation point, and the cooling efficiency is improved. The first and second Peltier elements Pe1, Pe2 are laminated, and all Peltier elements Pe1, Pe2 are driven by the common current controller A to miniaturize this photosensor. |
